ELECTRON-EMISSION FROM FOILS INDUCED BY ENERGETIC HEAVY-ION IMPACT

Doubly-differential cross sections have been measured and calculated for the electron emission produced by collisions of 3.5 MeV u-1 U38+ on thin carbon foils. The electron emission is observed in both forward and backward directions. Calculations are in reasonable agreement with the experimental results in both shape and absolute magnitude. At intermediate foil thicknesses, a double binary peak structure is observed that is due to 0-degrees binary electrons being elastically scattered to angle-theta along with those that are produced at theta and suffer no large-angle scattering events in the foil. Absolute electron yields show that several hundred electrons are released per ion impact. The computed time evolution of the forwardly emitted electrons indicates that the electrons tend to follow the ion for thin foils, but precede the ion in thick foils.